{
    let num='3px';
    console.log(Number.parseInt(num));
}
{
    console.log(Number.isFinite(3));
    console.log(Number.isFinite(NaN));
    console.log(Number.isFinite('你好中国'));
    console.log(Number.isFinite('10/0'));
}
{
    console.log(Number.isNaN(3));
    console.log(Number.isNaN(NaN));
}
{
    console.log(Number.isInteger(3));
    console.log(Number.isInteger(3.14));
}
{
    console.log(Math.trunc(3.14));
}
{
    console.log(Math.sign(3));
    console.log(Math.sign(-3));
    console.log(Math.sign(0));
    console.log(Math.sign(-0));
    console.log(Math.sign('你好'));

}